1-picolyl-3-phenyl ureas

ABSTRACT

Compounds of the formula IN WHICH X is nitro, methyl or trifluoromethyl, and n is an integer 1 or 2. The utility as post and pre-emergence herbicides of the compounds of the formula IN WHICH X is hydrogen, halogen, nitro, methyl, and trifluoromethyl, and n is an integer 1 or 2.

United States Patent Mihailovski [54] l-PICOLYL-3-PHENYL [72] Inventor:Alexander Miliailovski, Berkeley,

Calif.

[73] Assignee: Stauffer Chemical Company, New

York, NY.

[22] Filed: April 30, 1971 [21] Appl.N0.: 139,221

[52] US. Cl. ..260/295 E, 260/2955 D, 71/94 [51] Int. Cl. ..C07d 31/40[58] Field of Search ..260/295'E, 295.5 D

[56] References Cited UNITED STATES PATENTS Primary ExdminerAlan L.Rotman Att0meyDaniel C. Block, Edwin H. Baker, Albert J. Adamcik andHarry A. Pacini Rorig ..260/295 E I 57] ABSTRACT Compounds of theformula am x, CHzN-C-NH-Q 1% in which X is hydrogen, halogen, nitro,methyl, and trifluoromethyl, and n is an integer 1 or 2.

4 Claims, No Drawings l -PlCOLYL-3-PHENYL' UREAS This invention relatesto certain l-picolyl- 3-phenyl ureas which are new compositions ofmatter having the formula CHzILT-C-NHQ in which X is hydrogen, halogen,nitro, methyl and trifiuoromethyl, and n is an integer 1 or 2 Theabove-described compounds of this invention have been found to be activeherbicides ofa general type. That is, certain membersof the class havebeen found to be herbicidally effective against a wide range of plantspecies. A method of controlling undesirable vegetation of the presentinvention comprises applying an herbicidally effective amount of theabovedescribed compounds to the area or plant locus where control isdesired.

An herbicide is used herein to mean a compound which controls ormodifies the growth of plants. By a growth controlling amount is meantan amount of compound which causes a modifying effect upon the growth ofplants. Such modifying effects include all deviations from naturaldevelopment, for example, killing, retardation, defoliation,desiccation, regulation, stunting, tillering, stimulation, dwarfing andthe like. By plants it is meant germinant seeds, emerging seedlings, andestablished vegetation, including the roots and above-ground portions.

Among the halogen radicals represented by X in the foregoing formula,especially fluorine and chlorine are preferred, however, all thehalogens are included with this term, that is, fluorine, chlorine,bromine and iodine. Those skilled in the art will recognize that thedegree of substitution depicted by the foregoing formulas is limitedonly by the preselected values for n as an integer 1 or 2, stericconsiderations involved in placement of substituents about a moleculewithin a finite space. Those skilled in the art will appreciate theavailability and possibility of substitution about the pyridine moiety,i.e.,

The closest prior art consists of U .S. Pat. No. 3,128,280 whichdescribes various lalkoxylated/halogenated phenyl)- 3- pyridylmethylureas and their utility as pharmacological agents. The prior art doesnot disclose the utility as herbicides.

Preparation of the subject compositions readily proceeds by reacting apicolymethylarnine with an appropriate phenyl isocyanate containing therequisite substitutions. The reaction is generally carried out in aninert solvent, e.g., diethyl ether or benzene. This procedure is wellknown and can be found in the above-cited reference.

The compounds of the present invention and their preparation are moreparticularly illustrated by the following examples, Following theexamples is a table of compounds which are prepared according to theprocedures described herein.

EXAMPLE 1 Preparation of l-methyl- 1 -picolyl-3-phenyl Urea.

To a solution of 5.0 g. (0.041 mole) 2-picolylmethylamine in 30 ml.ethyl ether is added slowly 4.9 g. (0.041 mole) phenyl isocyanate in 30ml. ethyl ether with cooling in an ice bath. On completing the addition,the ice bath is removed and the reagents are stirred for an additionalhour at room temperature. The precipitated solid is filtered, washedwith a small amount of ethyl ether and dried. There is obtained 8.5

g. of the title compound, m.p. l38.5-l40 C. Yield is 86 percent oftheory. Structural proof is confirmed by infrared and proton magneticresonance spectroscopy.

EXAMPLE lI EXAMPLE n1 Preparation of 1 -Methyl- 1 -pico1yl-3-( 3-nitrophenyl) Urea In a similar procedure as hereinabove described, thetitle compound is prepared using 5.0 g. (0.041 mole) 2-picolylmethylamine in 30 ml. diethyl ether with 5.9 g. (0.036 mole)3-nitrophenyl isocyanate in 60 ml. diethyl ether. There is obtained 10.1g. of the title compound, a yellow solid, m.p. 127.5-129.5 C. Yield is92.5 percent of theory. Structural proof is confirmed by infrared andproton magnetic resonance spectroscopy EXAMPLE IV Preparation ofl-Methyll -pieolyl-3-(p-tolyl) Urea In a similar procedure ashereinabove described, the title compound is prepared using 5.0 g.(0.041 mole) 2- picolylmethylamine in 30 ml. diethyl ether with 5.4 g.(0.041 mole) p-tolyl isocyanate in 30 ml. diethyl ether. There isobtained 8.4 g. of the title compound, m.p. 88-90 C. Yield is 80.7percent of theory. Structural proof is confirmed by infrared and protonmagnetic resonance spectroscopy.

EXAMPLE V Preparation of 1-Methyl-l-picolyl-3-(3'-trifluoromethylphenyl) Urea In a similar procedure as hereinabovedescribed, the

' title compound is prepared using 3.0 g. (0.025 mole) 2-picolylmethylamine in 20 ml. benzene with 4.6 g. (0.025 mole)3-trifluoromethylphenyl isocyanate in 30 ml. benzene. There is obtained5.9 g. of the title compound, m.p. 85-87 C. Yield is 77.6 percent oftheory. Structural proof is confirmed by infrared and proton magneticresonance spectroscopy.

The is a table of the compounds which are prepared according to theaforementioned procedures. Compound numbers have been assigned to themand are used for identification throughout the balance of thespecification.

Other examples of compounds falling within the generic formula presentedherein, which are preparable by the aforedescribed procedures and whichmay be formulated into herbicidal compositions and applied as hereinillustrated, include:

Compound X, Pyridyl Number Substitution l 3-F,4-Cl 3 u 3-N0,,4-Cl 2 l23-No,,4-c1 3 1 l3 4-CH 3 l4 3,4-CI-l 2 l5 BIA-CH 3 l6 3,4-Cl 4 l7 3-F 4l8 4-CH 4 1'9 3-N0 4 4 l-IERBICIDAL SCREENING TESTS As previouslymentioned, the herein described compounds produced'in theabove-described manner are phytotoxic compounds which are useful andvaluable in controlling various plant species. Compounds of thisinvention are tested as herbicides in the following manner.

Pre-emergence herbicide test On the day preceding treatment, seeds ofseven different weed species are planted in individual rows using onespecies per row across the width of the flat. The seeds used are hairycrabgrass (Digitalis sanguinalis (L.) Scop.), yellow foxtail (Setariaglauca (L.) Beauv.), watergrass (Echinochloa crusgalli (1..) Beauv.),California red oat (Avena sativa (L.)), redroot pigweed (Amaranthusretroflexus (L.)), Indian mustard (Brassica juncea (L.) Coss.) and curlydock (Rumex crispus (L.)). Ample seeds are planted to give about 20 to50 seedlings per row, after emergence, depending on the size of theplants. The flats are watered after planting. The spraying solution isprepared by dissolving 50 mg. of the test compound in 3 ml. of asolvent, such as acetone, containing 1 percent Tween 20 (polyoxyethylenesorbitan monolaurate). The following day each flat is sprayed at therate of 20 pounds of the candidate compound per 80 gallons of solutionper acre. An atomizer is used to spray the solution onto the soilsurface. The flats are placed in a greenhouse at 80 F. and wateredregularly. Two weeks later the degree of weed control is determined bycomparing the amount of germination and growth of each weed in thetreated flats with weeds in several untreated control flats. The ratingsystem is as follows:

0 no significant injury (Approximately 0-10 per cent control) 3 slightinjury (Approximately 10-40 per cent control) 6 moderate injury(Approximately 40-70 per cent control) 9 severe injury or death(Approximately -100 per cent control) An activity index is used torepresent the total activity on all seven weed species. The activityindex isthe sum of the numbers divided by 3, so that an activity indexof 21 represents complete control of all seven weeds. The results ofthis test are reported in Table II.

Post-emergence herbicide test Seeds of five weed species, includinghairy crabgrass, watergrass, California red oats, Indian mustard, andcurly dock and one crop, pinto beans (Phaseolus vulgaris), are plantedin flats as described above for preemergence screening. The flats areplaced in the greenhouse at 72-85 F. and watered daily with a sprinkler.I

About 10 to 14 days after planting, when the primary leaves of the beanplant are almost fully expanded and the first trifoliate leaves are juststarting to form, the plants are sprayed. The spray is prepared byweighing out 50 mg. of the test compound, dissolving it in 5 ml. ofacetone containing 1 percent Tween 20 (polyoxyethylene-sorbitanmonolaurate) and then adding 5 ml. of water. The solution is sprayed onthe foliage using an atomizer. The spray concentration is 0.5 percentand the rate would be approximately 20 lb/acre if all of the spray wereretained on the plant and the soil, but some spray is lost, so it isestimated that the application rate is approximately 12.5 lb/acre.

Beans are used to detect defoliants and plant growth regulators. Thebeans are trimmed to two or three plants per flat by cutting off theexcess weaker plants several days before treatment. The treated plantsare placed back in the greenhouse and care is taken to avoid sprinklingthe treated foliage with water for 3 days after treatment. Water isapplied to the soil by means of a slow stream from a watering hosetaking care not to wet the foliage.

Injury rates are recorded 14 days after treatment. The rating system isthe same as described above for the pre-emergence test where (3), (6),and (9) are used for the different rates of injury and control. Theinjury symptoms are also recorded. The maximum activity index forcomplete control of all the species in the post-emergence screening testis 18. This index represents the sum of the rating numbers obtained withthe six plant species used in the test divided by 3. The herbicideactivity index is shown in Table II.

TABLE II I-IERBICIDAL ACTIVITY SCREENING RESULTS Herbicidal ActivityIndex Screened at 8 lb/A 2] 70-l00% control of all seven plant speciestested pre-emergence.

I8 70-l00% control of all six plant species tested post-emergence.

The compounds of the present invention are used as pre-emergence orpost-emergence herbicides and are applied in a variety of ways atvarious concentrations. In practice, the compounds are formulated withan inert carrier, utilizing methods well-known to those skilled in theart, thereby making them suitable for application as dusts, sprays, ordrenches and the like, in the form and manner required. The mixtures canbe dispersed in water with the aid of a wetting agent or they can beemployed in organic liquid compositions, oil and water, water in oilemulsions, with or without the addition of wetting, dispersing oremulsifying agents. An herbicidally effective amount depends upon thenature of the seeds or plants to be controlled and the rate ofapplication varies from I to approximately 50 pounds per acre.

The phytotoxic compositions of this invention employing an herbicidallyeffective amount of the compound described herein are applied to theplants in the conventional manner. Thus, the dust and liquidcompositions can be applied to the plant by the use of power-dusters,boom and hand sprayers and spraydusters. The compositions can also beapplied from airplanes as a dust or a spray because they are effectivein very low dosages. In order to modify or control growth of germinatingseeds or emerging seedlings, as a typical example, the dust and liquidcompositions are applied to the soil according to conventional methodsand are distributed in the soil to a depth of at least one-half inchbelow the soil surface. It is not necessary that the phytotoxiccompositions be admixed with the soil particles and these compositionscan be applied merely by spraying or sprinkling the surface of the soil.The phytotoxic compositions of this invention can also be applied byaddition to irrigation watersupplied to the field to be treated. Thismethod of application permits the penetration of the compositions intothe soil as the water is absorbed therein. Dust compositions, granularcompositions or liquid formulations applied to the surface of the soilcan be distributed below the surface of the soil by conventional meanssuch as discing, dragging or mixing operations.

The phytotoxic compositions of this invention can also contain otheradditaments, for example, fertilizers, pesticides and the like, used asan adjuvant or in combination with any of the above-described adjuvants.Other phytotoxic compounds useful in combination with theabove-described compounds include, for example,2,4-dichlorophenoxyacetic acids, 2,4,5- trichlorophenoxyacetic acid,2-methyl-4- chlorophenoxyacetic acid and the salts, esters and amidesthereof; triazine derivatives, such as 2,4-bis(3-methoxypropylamino-6-methyl-thio-S-triazine;2chloro-4ethylamino-6-isopropylarrfino-S-triazine, and2-ethylamino-4isopropylamino-6-methylmercapto-S triazine, ureaderivatives, such as 3-(3,4dichlorophenyl)-l,l-dimethyl urea and3-p-chlorophenyl)-l ,ldimethyl urea and acetamides such as N,N-diallyachloroacetamide, and the like; benzoic acids such as 3-amina-2,5-dichlorobenzoic; and thiocarbamates, such as S-propyldipropylthiocarbamate, S-ethyldipropylthiocarbamate,S-ethylcyclohexylsethylthiocarbamate, S-ethylhexahydro-ll-I-azepine-l-carbothioate, and the like. Fertilizers usefulin combination with the active ingredients include, for example,ammonium nitrate, urea and superphosphate. Other useful additamentsinclude materials in which plant organisms take root and grow, such ascompost, manure, humus, sand and the like.

The concentration of a compound of the present invention, constitutingan effective amount in the best mode of administration in the utilitydisclosed, is readily determinable by those skilled in the art.

Various changes and modificationsv are possible without departing fromthe spirit and scope of the invention described herein and will beapparent to those skilled in the art to which it pertains. It isaccordingly intended that the present invention shall only be limited bythe scope of the claims.

What is claimed is:

l. A compound having the formula CH: Xu

in which X is nitro, methyl or trifluoromethyl, and n is an integer 1 or2.

2. A compound according to claim 1 in which the trifluoromethyl. pyridylring substitution is in the 2-position and X, is A compo n ccor ng toClaim 1 in which the 3nitro. pyridyl ring substitution is in the2-position and X is 4- 3. A compound according to claim 1 in which themethylpyridyl ring substitution is in the 2-position and X, is 5

2. A compound according to claim 1 in which the pyridyl ringsubstitution is in the 2-position and Xn is 3nitro.
 3. A compoundaccording to claim 1 in which the pyridyl ring substitution is in the2-position and Xn is trifluoromethyl.
 4. A compound according to claim 1in which the pyridyl ring substitution is in the 2-position and Xn is4-methyl.